[lld] r240919 - COFF: Allow mangled symbols as arguments for /export.
Rui Ueyama
ruiu at google.com
Sun Jun 28 15:16:41 PDT 2015
Author: ruiu
Date: Sun Jun 28 17:16:41 2015
New Revision: 240919
URL: http://llvm.org/viewvc/llvm-project?rev=240919&view=rev
Log:
COFF: Allow mangled symbols as arguments for /export.
Usually dllexported symbols are defined with 'extern "C"',
so identifying them is easy. We can just do hash table lookup
to look up exported symbols.
However, C++ non-member functions are also allowed to be exported,
and they can be specified with unmangled name. So, if /export:foo
is given, we need to look up not only "foo" but also its all
mangled names. In MSVC mangling scheme, that means that we need to
look up any symbol which starts with "?foo@@Y".
In this patch, we scan the entire symbol table to search for
a mangled symbol. The symbol table is a DenseMap, and that doesn't
support table lookup by string prefix. This is of course very
inefficient. But that should be probably OK because the user
should always add 'extern "C"' to dllexported symbols.
Modified:
lld/trunk/COFF/Config.h
lld/trunk/COFF/DLL.cpp
lld/trunk/COFF/Driver.cpp
lld/trunk/COFF/SymbolTable.cpp
lld/trunk/COFF/SymbolTable.h
lld/trunk/test/COFF/Inputs/export.yaml
lld/trunk/test/COFF/dll.test
Modified: lld/trunk/COFF/Config.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/COFF/Config.h?rev=240919&r1=240918&r2=240919&view=diff
==============================================================================
--- lld/trunk/COFF/Config.h (original)
+++ lld/trunk/COFF/Config.h Sun Jun 28 17:16:41 2015
@@ -22,13 +22,13 @@ namespace coff {
using llvm::COFF::WindowsSubsystem;
using llvm::StringRef;
-class Defined;
+struct Symbol;
// Represents an /export option.
struct Export {
StringRef Name;
StringRef ExtName;
- Defined *Sym = nullptr;
+ Symbol *Sym = nullptr;
uint16_t Ordinal = 0;
bool Noname = false;
bool Data = false;
Modified: lld/trunk/COFF/DLL.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/COFF/DLL.cpp?rev=240919&r1=240918&r2=240919&view=diff
==============================================================================
--- lld/trunk/COFF/DLL.cpp (original)
+++ lld/trunk/COFF/DLL.cpp Sun Jun 28 17:16:41 2015
@@ -419,8 +419,10 @@ public:
size_t getSize() const override { return Size * 4; }
void writeTo(uint8_t *Buf) override {
- for (Export &E : Config->Exports)
- write32le(Buf + FileOff + E.Ordinal * 4, E.Sym->getRVA());
+ for (Export &E : Config->Exports) {
+ auto *D = cast<Defined>(E.Sym->Body);
+ write32le(Buf + FileOff + E.Ordinal * 4, D->getRVA());
+ }
}
private:
Modified: lld/trunk/COFF/Driver.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/COFF/Driver.cpp?rev=240919&r1=240918&r2=240919&view=diff
==============================================================================
--- lld/trunk/COFF/Driver.cpp (original)
+++ lld/trunk/COFF/Driver.cpp Sun Jun 28 17:16:41 2015
@@ -566,6 +566,20 @@ bool LinkerDriver::link(llvm::ArrayRef<c
break;
}
+ // Windows specific -- resolve dllexported symbols.
+ for (Export &E : Config->Exports) {
+ StringRef Name;
+ Symbol *Sym;
+ std::tie(Name, Sym) = Symtab.findMangled(E.Name);
+ if (!Sym) {
+ llvm::errs() << "exported symbol is not defined: " << E.Name << "\n";
+ return false;
+ }
+ if (E.Name != Name)
+ Symtab.rename(E.Name, Name);
+ E.Sym = Sym;
+ }
+
// Make sure we have resolved all symbols.
if (Symtab.reportRemainingUndefines())
return false;
@@ -593,12 +607,9 @@ bool LinkerDriver::link(llvm::ArrayRef<c
writeImportLibrary();
// Windows specific -- fix up dllexported symbols.
- if (!Config->Exports.empty()) {
- for (Export &E : Config->Exports)
- E.Sym = Symtab.find(E.Name);
+ if (!Config->Exports.empty())
if (fixupExports())
return false;
- }
// Windows specific -- Create a side-by-side manifest file.
if (Config->Manifest == Configuration::SideBySide)
Modified: lld/trunk/COFF/SymbolTable.cpp
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/COFF/SymbolTable.cpp?rev=240919&r1=240918&r2=240919&view=diff
==============================================================================
--- lld/trunk/COFF/SymbolTable.cpp (original)
+++ lld/trunk/COFF/SymbolTable.cpp Sun Jun 28 17:16:41 2015
@@ -15,6 +15,7 @@
#include "llvm/LTO/LTOCodeGenerator.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
+#include <utility>
using namespace llvm;
@@ -173,6 +174,28 @@ Defined *SymbolTable::find(StringRef Nam
return nullptr;
}
+// Find a given symbol or its mangled symbol.
+std::pair<StringRef, Symbol *> SymbolTable::findMangled(StringRef S) {
+ auto It = Symtab.find(S);
+ if (It != Symtab.end()) {
+ Symbol *Sym = It->second;
+ if (isa<Defined>(Sym->Body))
+ return std::make_pair(S, Sym);
+ }
+
+ // In Microsoft ABI, a non-member function name is mangled this way.
+ std::string Prefix = ("?" + S + "@@Y").str();
+ for (auto I : Symtab) {
+ StringRef Name = I.first;
+ Symbol *Sym = I.second;
+ if (!Name.startswith(Prefix))
+ continue;
+ if (isa<Defined>(Sym->Body))
+ return std::make_pair(Name, Sym);
+ }
+ return std::make_pair(S, nullptr);
+}
+
std::error_code SymbolTable::resolveLazy(StringRef Name) {
auto It = Symtab.find(Name);
if (It == Symtab.end())
Modified: lld/trunk/COFF/SymbolTable.h
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/COFF/SymbolTable.h?rev=240919&r1=240918&r2=240919&view=diff
==============================================================================
--- lld/trunk/COFF/SymbolTable.h (original)
+++ lld/trunk/COFF/SymbolTable.h Sun Jun 28 17:16:41 2015
@@ -52,6 +52,11 @@ public:
// different symbol). Returns a nullptr if not found.
Defined *find(StringRef Name);
+ // Find a symbol assuming that Name is a function name.
+ // Not only a given string but its mangled names (in MSVC C++ manner)
+ // will be searched.
+ std::pair<StringRef, Symbol *> findMangled(StringRef Name);
+
// Windows specific -- `main` is not the only main function in Windows.
// You can choose one from these four -- {w,}{WinMain,main}.
// There are four different entry point functions for them,
Modified: lld/trunk/test/COFF/Inputs/export.yaml
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/COFF/Inputs/export.yaml?rev=240919&r1=240918&r2=240919&view=diff
==============================================================================
--- lld/trunk/test/COFF/Inputs/export.yaml (original)
+++ lld/trunk/test/COFF/Inputs/export.yaml Sun Jun 28 17:16:41 2015
@@ -48,4 +48,10 @@ symbols:
SimpleType: IMAGE_SYM_TYPE_NULL
ComplexType: IMAGE_SYM_DTYPE_NULL
StorageClass: IMAGE_SYM_CLASS_EXTERNAL
+ - Name: '?mangled@@YAHXZ'
+ Value: 16
+ SectionNumber: 1
+ SimpleType: IMAGE_SYM_TYPE_NULL
+ ComplexType: IMAGE_SYM_DTYPE_NULL
+ StorageClass: IMAGE_SYM_CLASS_EXTERNAL
...
Modified: lld/trunk/test/COFF/dll.test
URL: http://llvm.org/viewvc/llvm-project/lld/trunk/test/COFF/dll.test?rev=240919&r1=240918&r2=240919&view=diff
==============================================================================
--- lld/trunk/test/COFF/dll.test (original)
+++ lld/trunk/test/COFF/dll.test Sun Jun 28 17:16:41 2015
@@ -1,7 +1,8 @@
# REQUIRES: winres
# RUN: yaml2obj < %p/Inputs/export.yaml > %t.obj
-# RUN: lld -flavor link2 /out:%t.dll /dll %t.obj /export:exportfn1 /export:exportfn2
+# RUN: lld -flavor link2 /out:%t.dll /dll %t.obj /export:exportfn1 /export:exportfn2 \
+# RUN: /export:mangled
# RUN: llvm-objdump -p %t.dll | FileCheck -check-prefix=EXPORT %s
EXPORT: Export Table:
@@ -11,6 +12,7 @@ EXPORT-NEXT: 0 0
EXPORT-NEXT: 1 0x1008 exportfn1
EXPORT-NEXT: 2 0x1010 exportfn2
EXPORT-NEXT: 3 0x1010 exportfn3
+EXPORT-NEXT: 4 0x1010 mangled
# RUN: llvm-as -o %t.lto.obj %p/Inputs/export.ll
# RUN: lld -flavor link2 /out:%t.lto.dll /dll %t.lto.obj /export:exportfn1 /export:exportfn2
@@ -28,7 +30,8 @@ EXPORT-LTO-NEXT: 3 0x1030 expor
# RUN: lld -flavor link2 /out:%t2.exe %t2.obj %t.lib
# RUN: llvm-readobj -coff-imports %t2.exe | FileCheck -check-prefix=IMPORT %s
-# RUN: lld -flavor link2 /out:%t.dll /dll %t.obj /implib:%t2.lib /export:exportfn1 /export:exportfn2
+# RUN: lld -flavor link2 /out:%t.dll /dll %t.obj /implib:%t2.lib \
+# RUN: /export:exportfn1 /export:exportfn2
# RUN: lld -flavor link2 /out:%t2.exe %t2.obj %t2.lib
# RUN: llvm-readobj -coff-imports %t2.exe | FileCheck -check-prefix=IMPORT %s
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